Energy generation systems and methods are disclosed. An energy generation system includes a fuel tank configured to store a fuel in liquid form and a power generating device including a fuel cell or an internal combustion engine configured to receive the fuel and generate electrical energy with the fuel. The energy generation system also includes an expander connected between the fuel tank and the power generating device, the expander configured to receive the fuel as a gas and a generator connected to the expander so as to generate electrical energy when fuel passes through the expander.